<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        #d1{
            width: 150px;
            height: 150px;
            background-color: red;
            overflow: hidden;/*解决沾连问题*/
        }
        #d1>div{
            width: 50px;
            height: 50px;
            background-color:blue;
            margin-left: 50px;
            margin-top: 100px;
        }
        #d2{
            width: 50px;
            height: 50px;
            border: 2px solid red;/*设置边框*/
            border-radius: 30px;
        }
        #d3{
            width: 50px;
            height: 50px;
            border: 1px solid blue;

            padding-left: 50px;
            padding-top: 50px;
        }
    </style>
</head>
<body>
<div id="d3">内边距</div>
<div id="d2">边框测试</div>
<div id="d1">ces</div>
</body>
</html>